Porsche's new high performance Cayenne S Diesel will offer a staggering 850Nm of torque,while still returning 34mpg.

On sale in January, the new model features a 4.2-litre twin-turbocharged V8, developing just over 380bhp and more than twice the torque of a 911 Carrera.

The Cayenne S Diesel will hit 60mph in under six seconds, going on to a top speed of 157mph. At the same time, the model's derv-burning power plant - combined with a start-stop system - emits just 218g/km of CO2. In comparison, the petrol-powered Cayenne S manages only 27mpg and emits 245g/km of CO2.

The S Diesel will be priced from £58,243 - a £1,500 premium over its petrol equivalent, but still around £3,000 less than more economical but marginally slower S Hybrid.